1. Field of the Invention
The present invention relates to a fixing apparatus and an image forming apparatus.
2. Description of the Related Art
Requirements for picture quality have been raised to higher and higher level as an image forming apparatus for forming an image on a recording material has been used in a variety of fields. As one of factors which determine the picture quality, particularly, the degree of gloss of full-color image, smoothness of output image can be mentioned.
To meet such a demand, for example, Japanese Patent Application Laid-Open NO. 64-35452 and Japanese Patent Application Laid-Open No. 5-216322 have disclosed an image forming method of forming color images by heating and melting color toner images after the color toner images of thermoplastic resin are transferred to a recording material in which transparent resin layer of thermoplastic resin is formed. As a preferred fixing method of these image forming methods, a belt fixing apparatus has been proposed.
As this belt fixing apparatus, for example, the belt fixing apparatuses described in Japanese Patent Application Laid-Open No. 5-216580 and Japanese Patent Application Laid-Open No. 4-362679 have been known. In the belt fixing apparatuses described in the Japanese Patent Application Laid-Open No. 5-216580 and Japanese Patent Application Laid-Open No. 4-362679, a recording material bearing a non-fixed toner image is pressed and heated with the fixing belt composed of heat resistant film and this recording material is cooled while kept in firm contact with the fixing belt so as to harden the toner image and then, the recording material to which the toner image is fixed is separated from the fixing belt.
As a result, with the toner image buried in transparent resin layer of the recording material, the transparent resin layer and toner image fixed on a surface of the recording material are coagulated along the belt surface configuration and the entire surface of the recording material turns to a smooth one, so as to obtain a color image excellent in the gloss property.
As the recording material having resin layer used in such an image forming apparatus, various recording materials as described in Japanese Patent Application Laid-Open No. 2003-84477 have been proposed. Japanese Patent Application Laid-Open No. 2003-84477 has proposed an electronic photographic transfer sheet in coated with resin layer mainly composed of thermoplastic resin having a glass transition temperature of 85% or less in the thickness of about 10 μm.
However, under the above-described structure, the apparatus is stopped at the same time as detection timing of an error in the apparatus if the error occurs in the downstream of a cooling means. Thus, the recording material before cooling can stop on an endless belt. In the meantime, the fixing apparatus includes art for stopping transportation of recording materials located in the upstream relative to an error position at the same time when the error is detected in that fixing apparatus, such as jamming of the recording material, and discharging recording materials located in the downstream relative to the error position. Even if this art is applied to a conventional structure including the fixing belt, the recording material can stop on the endless belt when any error occurs in the downstream of the fixing apparatus.
The recording material after heating and pressurization adheres to the endless belt strongly until it is cooled so that it is fixed thereto. Thus, if the recording material is left on the endless belt before cooling, it is difficult to remove the recording material left in the fixing apparatus. Further, there is a problem that if the endless belt is damaged or there is left fragments of the recording material not separated within the apparatus, fixing property after an error occurs may drop.